This invention relates to integrated circuits, and more particularly to a system and method for tracking integrated circuit parts through the manufacturing process.
In the manufacturing of integrated circuit parts (xe2x80x9cIC partsxe2x80x9d), a wafer consists of several hundred die. A set of wafers is grouped together and called xe2x80x9clotsxe2x80x9d. At each step of manufacturing, a lot is processed and the resulting data about the lot can be stored in a database. Ideally, lots proceed through the manufacturing process together so that the database of information can be useful in analyzing problems or defects in specific lots.
Unfortunately, in the real world, wafers can get separated from their lots and placed in new lots. During some steps, lots can be subdivided or combined into larger lots. Since lots do not remain static, it is a very tedious procedure to reconstruct all information gathered about a particular lot of wafers. In addition, with the movement of wafers among lots, the integrity of the lot data is jeopardized since the data for a lot may be inaccurate or incomplete.
Providing a method or system for tracking IC parts individually, regardless of their movement among various lots would produce a more accurate, detailed, and useful database.
Such a system would enable the entire manufacturing process to become much more productive with respect to the use of equipment and personnel by IC parts being allowed to flow through processes without trying to keep the original lots grouped in a meaningful order. Trying to keep lots grouped for the purpose of data analysis can waste much time. The lots go through different steps and get split up based on performance, causing the lots to continually decrease in size. Because it is a much more beneficial use of assets to work with large quantities of parts than many small groups, it is advantageous to move IC parts with no regard to their original lots. A system which would allow free movement of IC parts while retaining the ability for data analysis would make the manufacturing of IC parts more efficient.
The present invention solves the above-mentioned problems in the art and other problems which will be understood by those skilled in the art upon reading and understanding the present specification. The present invention provides an apparatus and method for tracking data for individual integrated circuits through the manufacturing process by programming an individual part identifier into a nonvolatile portion of the integrated circuit and maintaining a database of all manufacturing step statistics for later review and analysis. Typical uses for this data is in the review of the process steps used in producing particular lots of wafers of memory chips and tracking failure rates according to lot and wafers numbers.